Butterfly control valves were designed as automatic on-off block valves. They are classified into two groups as concentric butterfly valves and eccentric butterfly valves. Concentric butterfly valves are normally used in on-off block applications with a simple disk-inline with the center of the valve body. Eccentric butterfly valves are valves designed specifically for high performance throttling services, using a disk that is offset from the center of the valve body.

Butterfly dampers are the most common type of damper used in an acid plant. It can be used for flow control and shut off duties. It is cylindrical in shape. The damper consists of a disc, radially mounted on a shaft, inside a small segment of cylindrical duct. The shaft protrudes through the surface of the duct, to be accessible from outside the duct. It is typically used in round ductwork and zoning applications.

Butterfly dampers can be manufactured circular or rectangular, in a variety of configurations to suit a multitude of applications. These are mainly used for isolation, and can be used for control. It is manufactured in a variety of materials and can be supplied with refractory lining. Bearings can be mounted inboard or outboard, depending on the application.

Butterfly valve liners are mainly used for control valves, which serve purpose of sealing as well as bearing. These are designed for all service conditions and temperature resistance from -70°c to +250°c.

Butterfly valve is a very effective way to control and adjust the flow of a gas or a liquid through a pipe. The valve itself is in the form of a circular disk and doesn't really resemble a butterfly at all. A metal spindle runs through the center of the disk lengthwise. The disk will rotate as the spindle is turned. When fully closed, the disk will completely block the pipe and arrest the flow of the media since the pipe also has a circular cross section. As the spindle is turned (usually via a knob, a lever, or an electric motor), the disk will rotate away from its fully closed pipe-blocking position. When fully open, the disk will present only its thin flat side to the direction of the flow, impeding it by only a very tiny amount. It's this property that makes butterfly valves near perfect flow control devices.